1896 | _PROCARP AND CYSTOCARP OF PTILOTA 375 
anism by which the nuclear substance of the antherozoid could 
be carried to the female cell. But to make the problem still 
more complex there is the fact that the antherozoids are appar- 
ently rare, if not wanting, and yet cystocarpic fruit is very abun- 
dant. From the present examination, somewhat unsatisfactory 
as including only two species, the writer cannot but think it 
very probable that the cystocarp in this genus develops non- 
sexually. 
The evidence in favor of a theory of apogamy may be briefly 
summarized as follows: 
1. The entire absence of bodies attached to the tricho- 
Synes that could be identified as antherozoids impressed the 
writer as being very significant. 
2. Cystocarpic plants of P. serrata and P. plumosa with its 
variety filicina are common and bear immense quantities of 
fruit, there being as a rule a cystocarp at the end of every abor- 
tive pinnule (procarpic branch), and sometimes borne along the 
edge of the pinnules. Immense quantities of antherozoids, par- 
ticularly as they are non-motile in the Floridee, would be 
required to insure the development of such a profusion of cysto- * 
carps arranged in such a regular manner upon the frond, yet no 
antheridial plants of P. serrata or P. plumosa have been reported. 
It is natural to expect that antheridial plants will be found, as 
has been the case with Prilota elegans Bonnem, but they ought to 
exist in great quantity to produce such a profusion of fruit if the 
fystocarp is to develop as the result of a sexual act. 
3. The uniformity with which the cystocarp is developed 
from one carpogenous cell in the case of P. serrata and one of 
two cells in the case of P. plumosa can be explained in two 
Ways. Either the cell has been specialized as the female cell, 
of which there is no evidence in its structure or position, or it is 
the cell which by virtue of its age and situation is best fitted to 
8ive rise to the fruit apogamously. “As has been pointed out, 
the carpogenous cell is one of the oldest in the group of pro- 
sas Ss, and perhaps for that reason it may be the cell strongest 
mM Potentialities, best prepared to develop the fruit. At all 
